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ABSTRACT Scalable synthesis of two-dimensional molybdenum disulfide (MoS 2 ) via chemical vapor deposition (CVD) is of considerable interests for many applications in electronics and optoelectronics. Here, we investigate the CVD growth of MoS 2 single crystals on sapphire substrates by using thermally evaporated molybdenum trioxide (MoO 3 ) thin films as molybdenum (Mo) source instead of conventionally used MoO 3 powder for co-evaporation synthesis. The MoO 3 thin film source provides uniform Mo vapor pressure in the growth chamber resulting in clean and reproducible MoS 2 triangles without any oxide or oxysulfide species. Scanning electron microscopy, Raman spectroscopy, photoluminescence spectroscopy and atomic force microscopy characterization were performed to characterize the growth results. Very high photoluminescence (PL) response was observed at 1.85 eV which is a good implication of high optical quality of these crystals directly grown on sapphire substrate.
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Structural and electronic switching of a single crystal 2D metal-organic framework prepared by chemical vapor deposition
Abstract The incorporation of metal-organic frameworks into advanced devices remains a desirable goal, but progress is hindered by difficulties in preparing large crystalline metal-organic framework films with suitable electronic performance. We demonstrate the direct growth of large-area, high quality, and phase pure single metal-organic framework crystals through chemical vapor deposition of a dimolybdenum paddlewheel precursor, Mo2(INA)4. These exceptionally uniform, high quality crystals cover areas up to 8600 µm2and can be grown down to thicknesses of 30 nm. Moreover, scanning tunneling microscopy indicates that the Mo2(INA)4clusters assemble into a two-dimensional, single-layer framework. Devices are readily fabricated from single vapor-phase grown crystals and exhibit reversible 8-fold changes in conductivity upon illumination at modest powers. Moreover, we identify vapor-induced single crystal transitions that are reversible and responsible for 30-fold changes in conductivity of the metal-organic framework as monitored by in situ device measurements. Gas-phase methods, including chemical vapor deposition, show broader promise for the preparation of high-quality molecular frameworks, and may enable their integration into devices, including detectors and actuators.
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- Award ID(s):
- 1848046
- PAR ID:
- 10200142
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 11
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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